[GRASS5] Re: gis.m

[Michael Barton]

Kirk,

Thanks for continuing to test the new GIS Manager. V.what is a replacement
for d.what vect because d.what.vect REQUIRES you to interact with a xdisplay
(tektronic emulation) to  work. V.what does not require this. It is like
r.what. It takes input xy coordinates and returns the attributes linked to
the vector feature at that coordinate. V.what is a bit more flexible than
d.what.vect in that you can set the Œsnapping¹ distance. More importantly,
v.what can be used in any GUI and is not restricted to xdisplays, but
returns the same kind of information as d.what.vect. We need to have GRASS
modules that work with interfaces other than the old xmonitors if we want to
build a modern interface for GRASS. V.what does this.

The ­e flag in d.what.vect invokes a separate program, the ³form library²
which includes a TclTk form (and maybe associated C-code? I¹m not sure on
this). This is what allows you to edit the associated attributes for a
vector object. Theoretically, v.what‹or TclTk or other GUI code that calls
v.what‹could also invoke the form library (or something like it) to edit a
record. This would be very handy, though perhaps other methods might be
better‹such as doing a query that selected the associated attribute record
in a GUI table manager like SQLite Browser. IMHO, GRASS needs these kind of
attribute management tools. Moving to a new display model that does not
depend on a specific, antiquated display technology, will give us much more
flexibility to develop such tools.

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution and Social Change
Arizona State University
Tempe, AZ 85287-2402

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton




From: "Kirk R. Wythers" <kwythers at umn.edu>
Date: Wed, 1 Mar 2006 09:09:31 -0600
To: Michael Barton <michael.barton at asu.edu>
Cc: devel grass <grass5 at grass.itc.it>
Subject: gis.m


On Feb 27, 2006, at 6:19 PM, Michael Barton wrote:

> 
> The new gism does not use d.what.vect, but the new v.what. I'm not sure if
>  
> 
> it will show information in different layers or not. But that is something
>  
> 
> that should be fixable.


I am looking at the v.what and it may be just me, but I don't see that it is
a replacement for d.what.vect in that d.what.vect -e allows the user to
interactively click on a polygon and have a form open with that
polygon's attributes visible in an editable form. If an attribute has not
not been assigned yet (as in the case of a new attribute column),
d.what.vect -e can be used to "fill in" attributes. I'm just not seeing this
kind of interactive control in v.what. Am I missing something here?

>  
> 
> 
>  
> 
> BTW, I've now fixed the show columns and show data buttons in the vector,
>  
> 
> chart, and thematic panels so that they respect current database connections
>  
> 
> and layer settings. So you you can see the columns and data associated with
>  
> 
> your vector file.
>  

Also the "show attribute data" button does not seem to be working for me.
While the "show attibue colmns" butotn returns the output of v.info -c
map=t61v1_working layer=1to the output window:

INTEGER|cat
INTEGER|id
CHARACTER|type
CHARACTER|class

The "show attribute data" button returns:
GRASS 6.1.cvs (minnesota_utm):~ > table=t61v1_working
database=host=localhost,dbname=ts2325 driver=pg
2

It seems that the problem is the 2 at the end of the return. I get the
expected output if I send the first part of the command from the command
line:
GRASS 6.1.cvs (minnesota_utm):~ > db.select table=t61v1_working
database=host=localhost,dbname=ts2325 driver=pg

Michael, this may be due to the fact that I am using pg for attibute
management. Just thought you should know

Kirk






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